164 MOUNTAIN AND MOORLAND 



where there are fishes in abundance grow and prosper. 

 After half a dozen years or more they are fullgrown 

 and become restless. They leave their feeding-ground 

 sometimes a millpond, sometimes a slow-flowing 

 reach of river or stream and they descend the river 

 to the sea, travelling quickly by night. They seem to 

 go down to the deep water of the Atlantic Ocean, 

 from beyond the Hebrides southwards to the Azores, 

 and as they never come back again they probably die 

 after spawning. In all likelihood they are deep-sea 

 fishes which took long ago to exploring the fresh- 

 water, just the opposite of the Salmon, which is a 

 freshwater fish that has taken to feeding in the sea. 

 There is a migratory impulse engrained in the Eel's 

 constitution, and the particular feature that we wish 

 to call attention to is the strength of this hereditary 

 impulse. It is not following the line of least resistance 

 to swim up against the stream, and yet the Elvers 

 must do it. It is extraordinary the persistence with 

 which they overcome obstacles, even circumventing 

 waterfalls. They get up into Lake Constance, though 

 that is above the Falls of the Rhine ; they get up into 

 Lake Superior, though that is above the Falls of 

 Niagara. The conundrum is a little difficult, but the 

 answer is in the word " circumventing," and it is 

 illustrated on a small scale in regard to some of the 

 waterfalls on what we are calling our stream. The 

 young Eels get up somehow, wriggling on the moss- 

 covered rocks by the sides of the cascade, wriggling 

 up even among the wet grass and herbage. Up at all 

 events they do get. 



Very different from young Eels and yet sometimes 

 confused with them are the "niners," or larval Lam- 



